United States Patent Application: 0040245086
We have many times described, in perhaps general terms, and referenced reports concerning, the process of indirect Coal liquefaction, wherein Coal is first thermally gasified, with or without the addition of Steam, to generate a synthesis gas that is then catalytically condensed into liquid hydrocarbons.
That is the sort of technology utilized by South Africa Synthetic Oil Limited, SASOL, in their extensive Coal liquefaction industrial operations; and, it is, as we have earlier documented, the sort of technology that is undergoing continuous improvement by SASOL, and their academic colleagues at South Africa's University of Witwatersrand,
We have also reported that some Carbon Dioxide is co-generated in the production of hydrocarbon synthesis gas from Coal, and that South African scientists have been at work on ways in which CO2 can be recycled in the production of additional hydrocarbons.
We note, as well, that some Methane is also generated in the course of manufacturing synthesis gas from Coal, and remind you of other of our reports concerning the fact that Carbon Dioxide and Methane can be catalytically reacted and combined, "reformed", either to generate additional synthesis gas, or to synthesize specific hydrocarbons.
Herein, we see that a team of South African scientists has devised a technology wherein the Carbon Dioxide and the Methane, as co-generated constituents of a hydrocarbon synthesis gas derived from Coal, can be "reformed" together, in that synthesis gas, without an initial separation and purification, and broken down into more of the basic Carbon Monoxide and Hydrogen required by the catalytic unit that ultimately condenses synthesis gas into liquid hydrocarbons.
Comment follows excerpts from:
"United States Patent Application 20040245086A1 - Production of Synthesis Gas and Derived Products
Date: December, 2004
Inventors: Andre Peter Steynberg, et. al., South Africa
Abstract: A process for upgrading raw synthesis gas comprising at least CH4, CO2, CO and H2, includes heating the raw synthesis gas by addition of energy derived from electricity to provide an upgraded synthesis gas comprising less CH4 and CO2 and more CO and H2 than the raw synthesis gas. The invention extends to a process for producing synthesis gas, which process includes reforming a hydrocarbonaceous gas feedstock which includes CH4 to raw synthesis gas comprising at least CH4, CO2, CO and H2, and upgrading the raw synthesis gas in a process which includes heating the raw synthesis gas by addition of energy derived from electricity to provide an upgraded synthesis gas comprising less CH4 and CO2 and more CO and H2 than the raw synthesis gas.
Claims: A process for upgrading raw synthesis gas comprising at least CH4, CO2, CO and H2, the process including heating the raw synthesis gas by means of an electrically driven plasma torch to provide an upgraded synthesis gas comprising less CH4 and CO2 and more CO and H2 than the raw synthesis gas, at least a portion of the electricity for the plasma torch being generated from waste heat from the upgraded synthesis gas.
Background and Description: Analysis of the efficiency of the Fischer-Tropsch process used by the applicant to produce liquid fuels shows that for one particular application only about 75% of carbon entering the process as feedstock ends up in the desired products of the process. The largest portion (about 38%) of the 25% of the carbon not ending up in the desired products, was found to be lost in the form of CO2, formed in synthesis gas production stages and concentrated in the Fischer-Tropsch hydrocarbon synthesis stage.
This invention relates to the production of synthesis gas and synthesis gas derived products. In particular, it relates to a process for upgrading raw synthesis gas, to a process for producing synthesis gas, and to a process for producing a synthesis gas derived product.
Analysis of the efficiency of the Fischer-Tropsch process used by the applicant to produce liquid fuels shows that for one particular application only about 75% of carbon entering the process as feedstock ends up in the desired products of the process. The largest portion (about 38%) of the 25% of the carbon not ending up in the desired products, was found to be lost in the form of CO2, formed in synthesis gas production stages and concentrated in the Fischer-Tropsch hydrocarbon synthesis stage.
The cost of producing oxygen for use in the production of synthesis gas represents about 53% of the costs of converting a carbonaceous or hydrocarbonaceous feedstock into liquid fuels, using the Fischer-Tropsch or similar processes. As will be appreciated, a process using less oxygen and which wastes less carbon and oxygen in the form of CO2, will have cost benefits over conventional processes.
According to one aspect of the invention, there is provided a process for upgrading raw synthesis gas comprising at least CH4, CO2, CO and H2, the process including heating the raw synthesis gas by addition of energy derived from electricity to provide an upgraded synthesis gas comprising less CH4 and CO2 and more CO and H2 than the raw synthesis gas.
According to a further aspect of the invention, there is provided a process for producing a synthesis gas derived product, which process includes: providing a raw synthesis gas comprising at least CH.4, CO2, CO and H2 (and) in a synthesis gas upgrading stage, heating the raw synthesis gas by addition of energy derived from electricity to provide an upgraded synthesis gas comprising less CH4 and CO2 and more CO and H2 than the raw synthesis gas; feeding the upgraded synthesis gas, as a feedstock, to a synthesis gas conversion stage; and in the synthesis gas conversion stage, converting the upgraded synthesis gas to a synthesis gas derived product.
The raw synthesis gas is heated using electrical energy, and in particular the raw synthesis gas may be heated by means of an electrically driven plasma torch (and it) is an advantage of the invention that the electrical energy can be generated using waste heat from the upgraded synthesis gas.
The process may thus include cooling the upgraded synthesis gas. Heat removed from the upgraded synthesis gas may be used to generate steam, which may in turn be used to drive a steam turbine of a steam turbine-driven electricity generator to provide the electricity for generating the plasma torch.
The cost of producing oxygen for use in the production of synthesis gas represents about 53% of the costs of converting a carbonaceous or hydrocarbonaceous feedstock into liquid fuels, using the Fischer-Tropsch or similar processes. As will be appreciated, a process using less oxygen and which wastes less carbon and oxygen in the form of CO2, will have cost benefits over conventional processes.
(As specified) the synthesis gas conversion stage is a Fischer-Tropsch hydrocarbon synthesis stage (or) is selected from the group consisting of a methanol synthesis stage, a higher alcohol synthesis stage, and an oxoalcohol synthesis stage.
According to yet a further aspect of the invention, there is provided a process for producing synthesis gas, which process includes gasifying a carbonaceous feedstock under conditions suitable to provide a raw synthesis gas comprising at least CH4, CO2, CO and H2; and upgrading the raw synthesis gas in a process which includes heating the raw synthesis gas by addition of energy derived from electricity to provide an upgraded synthesis gas comprising less CH4 and CO2 and more CO and H2 than the raw synthesis gas.
(And wherein the) carbonaceous feedstock may be a solid such as coal."
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We have already provided you with numerous authoritative references which describe the "bi-reforming" and
"tri-reforming" reactions, including one most recently in a Masters Thesis from West Virginia University, wherein Carbon Dioxide can be reacted with Methane, and/or with Steam, and made thereby to synthesize higher, and valuable, hydrocarbons.
Herein, such a Carbon Dioxide bi-reforming of Methane is being made to take place in a chemical reaction "sub-system", as it were, of an overall process intended to synthesize liquid hydrocarbon fuels from Coal.
Aside from what should be the obvious value of such a productivity-, and profit-, enhancing subsystem for a Coal conversion process, with it's attendant environmental compliance benefits, consider that it is also further authoritative confirmation of the fact that Carbon Dioxide, no matter where we get it, can be productively recycled, via reaction with Methane, in the synthesis of valuable hydrocarbons, such as the "methanol" and "higher alcohol", above.
Moreover, a close read of South Africa's US Patent Application reveals that all, or nearly all, of the needed energy is derived as a by-product of the overall process itself,
It also hints at the fact that at least some of the Oxygen needed in the initial generation of synthesis gas, from Coal, is recovered when the Carbon Dioxide, in the raw synthesis gas, is reduced with the Methane to form Carbon Monoxide and Hydrogen.
And, remember: Not only can we generate the needed Methane via the, as herein, gasification of Coal; we can, as per the 1912 Nobel-winning Sabatier process now being, as we've documented, further refined and improved by NASA, also synthesize it directly from Carbon Dioxide - whether we reclaim that Carbon Dioxide from the flue gas of a Coal-fired power plant, or, as some of our USDOE National Labs, such as Sandia and Los Alamos, have proposed, by using solar or other environmental energy, from the atmosphere itself.